1. Field of the Invention
The present invention relates to thermal dissipation of an electronic device, and more particularly to an electronic device with movable thermal transfer elements and a heat sink thereof.
2. Related Art
As the performance of various electronic products has been increasingly enhanced, the accompanying thermal dissipation problem becomes even serious, especially the thermal dissipation problem of portable electronic devices. As for a portable electronic device, such as a notebook computer, a handheld computer, a mobile Internet device (MID), an ultra mobile personal computer (UMPC), a casing thereof is designed under the principle of “being light, thin, short, and small”, so as to maintain the chic and portable features. Correspondingly, the space inside the casing of the portable electronic device seems quite limited, such that electronic elements configured within the casing must be arranged in a quite compact manner. As a result, the thermal energy produced by the electronic elements due to a long-time operation is easily accumulated within the casing of the portable electronic device, such that the temperature of the entire portable electronic device rises sharply in a short time. Therefore, if the thermal energy in the casing of the portable electronic device cannot be eliminated rapidly in time, the electronic elements are easily resulted to work continuously in a high-temperature operating environment, which certainly influences the normal operation of the portable electronic device and even results in the damage of the electronic elements due to being overheated.
In order to improve the overall thermal dissipation efficiency of the system, most standard portable electronic device, e.g., a notebook computer, employs a heat sink component formed by combining a heat sink fin set with an electronic fan and a thermal transfer pipe to dissipate thermal energy. The heat sink fin set includes thermal transfer blocks and fins extended from the thermal transfer blocks. The thermal energy of a heat source is conducted to the fins via the thermal transfer blocks or the thermal transfer pipe. The electronic fan produces an airflow that passes through the fins to take away the thermal energy on the fins. However, as for a handheld electronic device with a smaller volume, e.g., the MID, since the inner space thereof is quite limited, in view of the factors that an inner heat source thereof produces less thermal, a fan configured therein may produce noises, and other problems, the handheld electronic device usually adopts merely a plate-shaped heat sink or adds fins on the heat sink, which is sufficient for meeting the thermal dissipation requirement of the system.
Recently, due to the continuous increasing of the chip processing clock, as well as other factors, the handheld electronic device has an increasingly high requirement for the thermal dissipation. However, the handheld electronic device still does not have sufficient inner space for disposing an electronic fan, but is merely configured with more fins. As a result, there is almost no gap between distal ends of the fins and the casing of the handheld electronic device. Therefore, without the assistance of the airflow, the thermal energy on the fins is directly conducted to the casing, such that the temperature of the casing rises continuously. The handheld electronic device is mainly provided for a user to operate while holding it in a palm and is seldom put on a desk for use, so that the excessively high temperature of the casing will result in less comfortableness of the user when holding it, thereby influencing the user's desire to purchase such handheld electronic device. In addition, the fins of the general heat sink fin set are vertically disposed on the thermal transfer blocks. However, the handheld electronic device is mostly used in a tilted state. Therefore, the hot air with a high temperature at the bottom of the fins cannot flow upward smoothly, such that the air convection around the fins is hindered, thereby reducing the thermal exchange efficiency of the heat sink fin set.